secret strings (was: lexbind: how to replace lexical-let approach to hide secrets)

[Stephen J. Turnbull]

Ted Zlatanov writes:

 > SJT> In the end it's up to the application to manage these secrets.
 > 
 > I strongly disagree that the consumer should have to wipe secrets when
 > done with them.  That simply shifts the burden of managing secrets
 > without easing it.

(defmacro with-secret-strings (variable-list &rest body)
  `(unwind-protect (progn ,@body)
     (mapc #'wipe-secret-string ,variable-list)))

Was that so hard?

 > Obviously data has to come from somewhere.  It can come from the
 > environment and from files and from IPC and from process pipes.  Emacs
 > can provide functions that read directly from those sources into a
 > secret string.

Sure.  One for every such source ....

 > Hiding secrets from backtraces and printing is another matter.  That we
 > can do with `lexical-let' or the approach Stefan showed so I think it's
 > a solved problem.  I've changed the subject to reflect we're discussing
 > "secret strings" now, though the name is not very good.

Well, I don't care about the name, but I don't see a use case where
the users are really protected.